A way to pay where everybody knows your name

Square Inc., which is quickly making a name for itself in the mobile payments arena, on Wednesday released a new iPhone version of its Card Case app that lets you make a purchase just by saying you own name.

And it’s hands-free – you don’t have to reach into your pocket to hand over cash, a credit card or your phone.

The app takes advantage of geo-fencing technology included in Apple’s new iOS 5 mobile operating system, so right now, it’s only available for Apple devices. (Square is working on a Card Case update for Android devices as well.)

In the previous version of Card Case, you would still have to launch the app and press a tab for a merchant. But the update includes automatic tabs that activate when the app recognizes that you and your phone are within 100 meters (328 feet) of a participating merchant.

I had the chance to try the app for lunch today at the weekly Off the Grid mobile food truck gathering in the alley next to The Chronicle building, which is also where Square has its headquarters.

I just walked up to the Senor Sisig truck, ordered three tacos and said, “Put it on Benny Evangelista.” The clerk found my account and moments later, an electronic receipt beamed into my phone.

The hands-free option does have a price limit. If I ordered $50 worth of tacos, I would have to key in a password.

A Square spokesman said some mobile merchants won’t be able to enable the automatic tabs because they don’t have a permanent physical location, but there are a growing number of merchants that can.

The app also lets you browse a directory of more than 20,000 participating merchants, and you can filter the list by those that are nearby. You can also view menus and find directions.

And the app brings in Twitter feeds from those merchants and from customers who are tweeting about them. That new feature is a no-brainer since Square CEO Jack Dorsey is also Executive Chairman of Twitter.